Furnace for roasting ores.



No. 673,174. Patented Apr. 30, |901. A. P. umsu. FURNACE FOR RUAVSTING DRES.

(Application led Sept. 6, 1 900.) (Nn Modelv.) 2 Sheets-Sheet l.

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Nth-673,174. Patented Apr. 30, |90I. A. P.. BRIEN.

FURNACE FR RDASTING DRES. (Appl e lns1 d sept e 1900) 2 sheefs-sneef 2.

(No Mode.)

. l witmzowo Houtman UNITED STATES y PATENT OFFICE.

ANDREW PATRICK OBRIEN, OF RICHMOND, VIRGINIA.

FURNACE FOR ROASTING ORES.

SPECIFICATION forming part of Letters Patent No. 673,174, dated April 30, 1901.

`Application filed September 6, 1900. Serial No. 29,205. (No model.)

To all whom it may concern:

Be it known that 1, ANDREW PATRICK OBRIEN, acitizen of the United Stat-es, residing at Richmond, in the county of Henrico and State of Virginia, have invented certain new and useful Improvements in Furnaces for Roasting Ores; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to furnaces for roasting ores, and has for its object the general improvement of the details of construction whereby improved results are Obtained in the use of the device.

With this object in view my invention consists in the improved construction, arrangement, and combination of parts hereinafter fully described and afterward specifically claimed. e

In the accompanying drawings, Figure 1 is a vertical sectional view on the line 1 1 of Fig. 2. Fig. 2 is a top plan View, partly in section. Fig. 3 is a detail view, on a reduced scale, of the central hollow shaft. Fig. 4 is a detail view of the feed mechanism, the greater portion of the connecting-rod being broken out to shorten the figure. Fig. 5 is a detail sectional view of a portion of the hollow shaft, showing one of the apertures for receiving a raker-arm.

Like parts are indicated by the same 11umerals in all the figures of the drawings.

The improvements embodied in this inven-l tion are applied to that class of furnaces which contain a series of substantially horizontal shelves or trays of brick or similar material having discharge-openings in each tray to the tray below alternately at the circumference and at the center, a central shaft being prof vided having arms extending over these iioors and carrying teeth or rabbles for the purpose of raking or stirring the ore on the trays.

In the accompanying drawings, 5 indicates the usual brick cylinder or shell, which in this instance is embraced in the steel shell 6, composed of curved plates, as shown in Fig. 2, and butt-jointed, so as to closely fit the brick shell and leave a smooth surface on the outside to permit of bolting to T iron posts circumference for feeding their contents upon the alternate shelves or trays 9.

13 indicates the roof of the furnace, preferably of plate metal, through which are a series of outlets le 14 for gas arranged in a circle and covered by a horseshoeshaped inner end 15 of a gas-discharge pipe 16, the area of the pipe 16 being about equal to the combined area of the series of openings 14E.

17 indicates a central hollow vertical shaft, which is tapering, being largest at its upper end and mounted at its lower end upon ballbearings 18 and hollow pedestal 19, which, in connection .with a horizontal pipe 20, forms a duct for cold air from the outside to the tapering shaft. This shaft is shown in sectional detail in Fig. 3 and is provided with openings 21, having upper and lower key-seats 22 23, said openings being located diametrically opposite and in such position as to be between the shelves 9 and 11 when the parts are as# sembled.

24, 25, 26, and 27 are upwardly-projecting annular iianges, which, together with corresponding downwardly-extending annular Iianges 28 on the outside of the tapering shaft 17, form supports for the tapering shaft, the flanges of the shaft dropping over the flanges ,24 25 26 27 and the joints being properly luted. i p

29 29, duc., indicate raker or stirrer arms, which in assembling the parts are projected through openings 30, through the shell indicated in dotted lines in Fig. 2 into the center of the hollow shaft 17, and through the oppositely-located openings 21, said arms being hollow and abutting one against the other in the center of said shaft. The openings 21 may be tapered to correspond with the outer shape of the arms, and the arms are secured therein by means of keys 31, fitting into the key-seats. The principal supports, however, of the arms loo are long bolts or rods 32, extending entirely through two opposite abutting arms and secured by nuts 33.

Secured upon the lower end of the` hollow shaft 17 is a circularplate 34arranged below the bottom shelf 53 of the furnace, .which plate 34 is provided on its under surface with teeth 35, forming a large bevel gear-wheel, that part of the plate beyond the gear-wheel being formed into an ash-pan 36.

37 indicates a bevelpinion -mounted on a horizontal driving-shaft 33 and meshing with the large bevel gear -wheel 35. Upon this shaft 38 is an eccentric 39, the connecting-rod 40 of which may be adjustably connected with a lever 41, secured to a shaft 42, journaled in the shell above the roof of the furnace and carrying a ratchet-wheel 43 in engagement with a pivoted pawl 44, carried by the lever 41. On the shaft 42 is a screw feed or conveyer 45, which serves to feed the ore which is dropped in a hopper 46 toward the circumference of the shell of the furnace, so as to drop it through a space at the outer ci reumference of the roof 13 upon the upper tray or shelf 9.

The lower shelf or bottom 53 of the furnace may be made of iron, as shown, or brick, if desired,and is arranged to discharge the ashes vof the furnace at its outer edge. It has a central aperture surrounding the hollow shaft 17 and a lute for preventing the escape of burned ore at this point.

The raker or stirrer arms are provided with upper and lower teeth 47, which are staggered or alternated in position, so that by reversing an arm different circles of the contents of the trays or shelves wil-l be operated upon.

In furnaces of this class as heretofore made a hollow post has been provided, in which raker or stirrer arms are inserted, which arms abut at the centerof the shaft; but in all such constructions with which I am acquainted the arms were so secured in the shaft as to render it necessary to tilt them before they could be removed through the holes in the sides of the shell. This necessitated the use of larger holes in the shell, and consequently the placingofthe trays or shelves at a greater distance apart.

With the construction herein described by the removal of the securing-bolts the stirrer or raker arms may be removed in horizontal lines, this requiring holes in the shell of a u sizeV only suicient to permit of their passage.

The obvious advantage of this construction will be apparent at a glance. By virtue of the means herein described for securing the verticalhollow shaft said shaft may be bodily removed out of the top of the furnace and replaced therein without cooling the furnace.

Operating in the ash-pan 36 is alscraper 48, which is adjustable to the desired extent to regulate the admission of air to the furnace, said scraper extending through the wall of the furnace to the outside thereof and provided With an operating-handle 49. The scraper 48,

\ shaft direct.

by extending inwardly over ,the ash-pan operates to maintain the `ashes in said pan ata certain height bythe revolution of the pan with respect to the said scraper. The scraper removes all ashes above a certain height in the pan, according to. the position to which the said scraper is adjusted. The scraper is pivoted on a bracket 50, arranged on the inner wall of the furnace, and adjusting-holes 51 are provided in one of the posts 7, and a'longitudinal slot 52 is provided in'theoperatinghandle of the scraper, so that the scraper can be adjusted to the desired position and held in such position by means of a pin passed through the slot into one of the adjustingholes. By this means the inner end of the scraper or Scrapers can be held at different heights above the ash-pan 36. It will be evident that when the inner end of the scraper is lifted more ash will be allowed to accumulate on the pan 36 than when in a lowered p0- sition, and the air-inlet space between the said pan and the lower edge of the furnace- Wall will be comparatively small; but when the scraper is lowered more ash will be scraped from the pan 36 and the air in the space will be correspondingly increased.

Heretofore it has been customary to drive the feed mechanism from the main central With my construction the feed is driven from the main driving-shaft with an eccentric and pawl lever, such feed being adjustable Without the necessity of going on top of the hot furnace. In my construction the ore in feeding is passed over the hot bottom of the conveyer-trough and dried, and the main central shaft is open `to the cool outer air, which always keeps the shaft cool. The construetionof the shell with the T angle-iron posts and butt-jointed plates leaves an even cylindrical surface for a brick liningsaving in the construction of brickwork, the posts also carrying the weight of the entire furnace. Admitting the feed away from the central shaft is another advantage, as is also the construction of cinder-carrying pans with adjustable scraper, as shown. Taking the gas from the center of the roof or top shelf with a horseshoe-shaped collector-pipe covering several small openings does not weaken the roof or shelf like one large opening, which is the usual way of taking off the gas.

Having thus described the invention, what is claimed, and desired to be secured by Letters Patent, is-

1. In an ore-roasting furnace havingaseries of superposed hearths provided with central openings, a downwardly-tapering shaft revolubly mounted in the furnace and passing through the central holes of the hearths, the said shaft being provided with anges, and alternating hearths with corresponding flanges for forming sealing means, the size of the holes and the flanges of the shafts being relatively proportioned sothat the shaft may be withdrawn from `the furnace through the holes in the several hearths,substantially as described.

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2. In an ore-roasting furnace, the combination of a series of superposed hearths having central holes, a downwardly-tapering hollow shaft inserted through the said holes, sealingflanges arranged upon the tapering shaft and at the holes of alternate hearths, the proportionate size of the flanges and the holes being such that the shaft can be easily withdrawn from the furnace by lifting the same through the top thereof, raker or stirrer arms carried by the shaft, a hollow pedestal supporting the hollow shaft, and a cold-air pipe in connection with the hollow pedestal, and shaft, whereby a cooling-blast may be driven entirely through the shaft, substantially as described.

3. In an ore-roasting furnace, the combination with a hollow downwardly-tapering central shaft revolubly supported and provided with tapering sockets having upper and lower key-seats, of raker or stirrer arms provided with keys, said arms and keys fitted into the sockets and key-seats, and alternating upper and lower teeth on the raker and stirrer arms, whereby the said arms may be reversed, substantially as described.

4. In an ore-roastingfurnace, the combination of a hollow, downwardly-tapering, central shaft, revolubly supported and provided with diametrically opposite, tapering sockets or apertures opening into the central cavity of the shaft, rakerarms having tapered heads fitted into said sockets and abutting at their inner ends within the cavity of the hollow shaft, means for passing a cooling agent through the shaft, whereby the shaft and said Y abutting ends may be kept cool and means for holding the said raker-arms in position, the construction being such that the shaft and arms may be readily removed from or inserted within the furnace, substantially as described.

5. In an ore-roasting furnace, the combination with a hollow downwardly-tapering central shaft revolubly supported and provided with diametrically opposite tapering sockets,

of raker-arms having tapering heads fitted in said sockets and abutting at their inner ends in the centerof said hollow shaft, and bolts extending entirely through opposite pairs of raker-arms and the central shaft and having suitable nuts for securing them in position, substantially as described.

6. In an ore-roasting machine, the combination with a central hollow shaft revolubly su pported and a suitable shell provided with diametrically opposite holes, of raker-arms secured in the hollow shaft diametrically opof their wi thdrawal in horizontal lines through said holes, substantially as described.

7. In an ore-roasting furnace, the combination with a hollow pedestal, and a pipe serving as a cold-air duct communicating therewith,of ahollow,central shaft stepped or journaled at its lower end upon said pedestal and forming a continuation of the air-duct, and raker-arms extending into the cavity of the shaft, whereby said shaft, as well as the attaching ends of the raker-arms, may be kept cool by a blast of air forced through the hollow shaft, substantially as described.

8. In an ore-roasting furnace, the combination with the shell, the trays or shelves, the hollow central shaft revolubly supported and raker-arms, of an annular cinder-pan arrangedopposite the lower end of said shaft and provided with adjustable Scrapers, substantially as described. Y

9. In an ore-roasting machine, the combination with a suitable shell, superposed trays or shelves, central shaft revolubly supported, and raker-arms carried thereby, of a circular cinder-pan secured to the central shaft, teeth on the lower face of said pan forming a bevelgear, a drive-shaft, and a bevel-gear engaging the bevel-gear teeth of the cinder-pan, substantially as described.

lO. In an ore-roasting furnace, a gas-discharging mechanism consisting of a circular series of holes in the top of the furnace, a large gas-discharge pipe, and a horseshoeshaped extension of said discharge-pipe covering said circular series of openings, substantially as described.

l1. In an ore-roasting furnace, the combination of a revoluble shaft, an ash-pan secured thereto and revolving therewith, a discharge-scraper adapted to extend inwardly from the shell of the furnace over the said pan for regulating the height of the ashes in the said pan, the said scraper being provided with a handle extending outside the furnace, and means for adjusting the scraper to different positions for regulating the height of the ashes in the pan and thereby the amount of air admitted to the furnace, substantially as described.

In testimony whereof I hereunto ax my signature in presence of two witnesses.

ANDREW PATRICK OBRIEN.

Witnesses:

J. W. GooDE, G. W. TAYLOR.

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